Cancer risk associated with exposure to asbestos is well established. The greatest risk is that suffered by workers; however, environmental exposure as in households of asbestos workers may also result in disease. While mesothelioma has been found among household contacts, quantitation of this risk has not been undertaken, nor is it known whether other asbestos-associated diseases (lung cancer, GI cancer) are also increased. In another study, we have established the mortality experience of a cohort of asbestos factory workers. In this investigation, we will study the mortality experience 1946-1980 of the family contacts of these asbestos factory workers, who resided in their households during the period of factory employment 1941-1945. Some data are available concerning the levels of their exposure. In a preliminary feasibility study, we have determined that the family cohort can be identified and traced, and that cause of death can be established for those who have died. Thus, it will be possible to evaluate the family contact experience in relation to an occupationally-exposed group, exposed to precisely the same fibers, from the same source, in the same years, in the same geographical area. Only the exposure circumstances and the intensity of exposure will have varied. It may be of interest that in the initial feasibility study, four cases of mesothelioma were found. Although three were alive when first discovered, all are now deceased, death having occurred approximately thirty years from onset of household exposure.